Fate Impure World
by Fourth Pear
Summary: Death, the first space-time technique. When souls pierce the veil they leave the world of the living and move on to another. With that in mind, it really should have occurred to people that through death other worlds could be reached. Because when someone who only exists as a soul is called towards another world, well, there's really nothing in their way. NarutoXSakuraSaber


**Hey all, I'm back with a new fic! I wanted to do a crossover where servants aren't as restricted as they would be in an actual Grail War, but, I also wanted to avoid giving Naruto some super powered Servant like Gilgamesh. He is a good character because he is weak despite his great potential and slowly comes into his own strengths even after facing so many obstacles. As Servants are usually summoned based on compatibility with their masters (unless a specific reagent is used *wink* *wink*) I thought his servant should have things in common with him.**

 **Disclaimer: Naruto is owned by Masashi Kishimoto. Fate/Stay Night is owned by TYPE-MOON.**

* * *

They should have known this mission would go tits up.

Honestly, even if he _didn't_ have kind of a track record with mis-ranked missions the parameters of _this_ mission should have set off warning bells the moment he heard them. After all, they had been assigned to investigate what was believed to be one of old snake-face's bases. Abandoned though it seemed to be they _really_ should have seen this coming.

Okay, well, not _this_ exactly but, ya'know, something to this effect. Something like the base not being as abandoned as it appeared.

*Bang!*

The heavy door at his back-one that would not look out of place on a bank vault-shook with the great weight of the creatures that threw themselves at its frame, attempting to break it down with their own bodies to get to him.

 _Food._

With every tremor and shake his chakra enhanced hearing could make out the surrounding wall break just a little more, the steel itself warp ever so slightly. Stone and metal holding against the unholy onslaught, but they would not hold indefinitely.

He let out a long, tremulous, breath. His hands shook even as his fingers dug into his thighs with bruising force.

He was scared.

His team was gone ( _'Probably dead'_ , a traitorous thought whispered.), he was trapped a mile underground with his only avenue of escape blocked by whatever _abominations_ Orochimaru and his men had cooked up before abandoning this place, and he had been injured badly as well-a large chunk of his side completely clawed off by some ravenous beast. It was healing steadily but at the cost of being a constant drain on his chakra reserves and stamina. What's worse, by the time anybody would think to send out reinforcements or a search party he would most likely be long gone.

Dead.

He was going to die here. Alone, in the dark, without ever becoming Hokage.

"Like hell!" he denied through clenched jaw. With great effort he pushed himself up to his feet and began to walk on trembling legs. He wasn't going to make this easy for those _things_ which meant sitting around on his ass with his back to them and waiting for death was not an option. As he slowly made his way to the opposite side of the chamber in search of a somewhat defensible position his foot landed on some kind of beaker or vial. With a startled shout he lost his footing and went tumbling into an old bookshelf. The aging and frail wood broke beneath his weight and he was soon buried under a pile of dusty tomes and scrolls.

' _Motherfucker!'_ he mentally cried in pain. His mouth was too busy to scream, clenching tightly in an effort to avoid biting through his own tongue as it was. For several long moments he simply laid there, the pain too great to even contemplate moving. He began to shift, then, and as he pushed his way out of the pile of junk he had been buried in another piece of scientific equipment fell off of his lap and began to roll across the floor. The sound deafeningly loud when compared to the deathly silence he found himself in.

'… _silence?'_

With a start he lifted his head and perked his ears, straining to hear anything beyond his own ragged breathing and racing pulse.

He found nothing.

No haunting growls, no scrapping of claws on stone, no crashes of malignant flesh against steel. He was alone.

A feeling of dread began to settle in his stomach. Those creatures had not let him alone for a _moment_ down here. They followed him regardless of their own health or well-being and seemed able to sense his presence even through meters of solid rock. If they had left him now it could only mean that something was coming. Something _bad_.

His struggles renewed, now with a panicked edge to them. If he were in full health he might have tried to sneak away while they were gone, but with almost half his stomach just _not there_ he doubted he would even be able to open the door. His regeneration was going full blast in order to stem the loss of blood and prevent infection which was a massive drain on his reserves in addition to the ridiculous amount of chakra he had spent ( _'wasted'_ ) in his initial attempt to escape this place. The two chūnin that had been teamed up with him had been overwhelmed by those things and torn apart, his hordes of kage bunshin little more than a momentary distraction against so many teeth, claws, and-he shuddered-appendages… He hadn't been able help them, hadn't been able to _save_ them. He didn't even know their names.

Gods, he hadn't even _seen_ Anko-taicho since they were separated at the start of this mess.

He hadn't been able to help any of them. He had been useless and now his lack of any real skills was going to kill him as well. He doubted he'd even be able to concentrate enough to perform a technique, that is, if he even had one that would be _worth_ something in this situation. Sage's balls if he survived this he was going to hunt down and learn as many supplementary jutsu as possible-especially doton techniques-even if he had to steal th-

*Whack!*

"Ow, damnit!" he yelped as a final scroll fell from the ruined shelf and landed on his head. With a pained growl he glared at the offending parchment and prepared to throw it before something caught his eye.

The entire base was lit by some kind of glowing crystals mounted on the walls in place of torches. While not enough to truly see everything the shadows hid they did provide a dim glow throughout the chamber he found himself in. Through this glow he caught sight of a familiar leaf symbol on the outside of the scroll he now held.

' _From Konoha?'_

His curiosity won out over the heavy panic he had been all but choking on seconds before. With a brief moment of concentration his hand was engulfed with enough chakra to give off a bright yellow glow. This allowed him to actually read the scroll he now held. With some trepidation he unrolled it to see what it held.

'-iyose: Edo Tensei'

' _Impure World…Resurrection?'_

The scroll was covered in damage due to age, mold, and what looked suspiciously like blood. As a result he could only make out a little over half the scroll itself. What he saw, however, was more than enough to light a fire he had almost snuffed out in his fear.

Hope.

'-is utsu c lls spirits e dead aid use-'

'-apable of using juts-'

A technique which summoned the dead to help the living. The odds of calling forth someone who actually _did_ have a jutsu that could help him was far greater than the odds of him developing one on his own before the monsters returned with whatever they were preparing. What's more, according to the scroll the jutsu was based entirely on fūinjutsu, something he excelled at if his lessons with Ero-sennin were any indication. He could do this, he could summon someone to help him. Already he was filling in the blanks on the half-destroyed sealing array the scroll contained. He would survived this! Make it home! Become hokage! This time ghosts were actually going to _help_ him!

With a mental struggle a luminous fountain of chakra erupted from his body forming a perfect circle around him free of debris. He then began to write out the large formula he needed on the floor. It took an ungodly amount of concentration to dull the pain in his side and steady his hand. He had no ink (and he would be carrying _that_ with him from now on), but, he did have something that was just as good.

His blood.

Soon Naruto had a huge array drawn up. A large spiral surrounded by what seemed like hundreds of kanji and symbols. He knelt in the center-diligently working-while leaving enough room for another person to stand or, well, whatever it was ghosts did.

* * *

The Edo Tensei technique was a dark jutsu developed by the Second Hokage to return the dead to life at the cost of one human sacrifice per summoned individual. Those summoned were simply spirits, souls, who through the jutsu forcibly possessed the sacrifice offered and used the dirt and ash of the Impure World to regain their original form. As they were still dead and, yet, were manifest in the world of the living the duality of their existence (their connections to both the _physical_ and _spiritual_ worlds) allowed them an unlimited supply of chakra.

The Nidaime had intended to use this jutsu as a means of disposing of his enemies while also reviving his allies, allowing them to continue fighting for Konoha and the Senju at the cost of their foes. Even his cynical worldview, however, had never been able to justify enslaving the spirits of the dead. To defile even his most hated enemies in such a way was something even he was not capable of.

Orochimaru had no such compunctions. Indeed, it could be said that he had no allies-only enemies and slaves-and thus needed a method to _control_ any spirits he summoned. The scroll Naruto held was the result of this need. In many ways it could be considered a prototype for the seemingly perfected technique Yakushi Kabuto would gain mastery of in the years to come.

However, most of the actual work Orochimaru had done on the technique had been destroyed when the scroll was damaged.

As a result Naruto possessed the core of the technique as well as some notes on binding a summoned spirit to the summoner's will. He then began filling in the blanks using his own knowledge of fūinjutsu. Only someone on the level of Jiraiya or the Yondaime should have been able to do this successfully, however, Naruto was no ordinary practitioner. As an Uzumaki he had an almost preternatural grasp on the art of sealing. Trained by possibly the greatest living sealmaster he had shown prodigious growth in skill over the course of his tutelage (Not that Jiraiya would ever tell his student just how good he was. The old perv wouldn't want to give him a big head.).

This should not have been enough.

Working on such a complex technique with such little time and no training in techniques that strayed into the realm of the dead _should_ have been impossible, even for an Uzumaki. Even one as ridiculously skilled as Naruto was.

Except, while Naruto did not have training in more necromantic techniques he _did_ have possibly the greatest example of them literally branded onto his very being.

Even before the knowledge of the Kyuubi's fate had been granted to him he had been studying the strange markings on his stomach for years. As a child with no knowledge of or training in fūinjutsu he had memorized it in its entirety. At seven he could draw it perfectly. This was due as much to his potential as it was to the fact that the seal was not simply marked onto his flesh. The Shiki Fūjin had been grafted onto his very _soul_. Even without knowing what it was he _knew_ it as well as he knew himself.

And so, as Naruto struggled to complete the half-destroyed technique he began drawing on his knowledge of the Shinigami's work to supplement his own learnings. By the time he had finished a completely new technique had been born.

A terrible roar filled the caverns he found himself in. With a start he realized that the beast that had made such a sound was not only larger than any of the monsters he had fought before but _closer_ than he was at all comfortable with.

Panic began to set in again as Naruto rushed to finish his work. With a final stroke of bloodied fingers his crimson array was completed and he began gathering as much chakra as possible. He had no way of knowing exactly how much power this jutsu would take, but, he did know that he could not fail. Whether the spirit he summoned could help him or if he even managed to summon one at all would be the only divider between life and death in this instance. With this in mind Naruto found himself pouring out every drop of chakra he had. The fox would take over his regeneration.

' _Tiger. Snake. Dog. Dragon!'_ he thought while moving through a surprisingly short set of hand signs, ending by clapping his hands together.

"Kuchiyose no Jutsu: Edo Tensei!"

Suddenly, the ground began to shake as something large and _angry_ began barreling towards his position. He really _did_ have only one shot now.

' _Come on! Come on! Work!'_

The shift of his chakra caused a gentle breeze to flow throughout the chamber. As the seal began to glow brighter so did the wind gather into a whirlwind around him. Naruto-with all of his attention on gathering and directing chakra-failed to notice a single cherry blossom flutter off of his traveling cloak and gently land in the center of the glowing spiral, nor the strange markings that appeared on the back of his hand.

A reagent was presented.

A door to the afterlife was opened.

A contract was made.

With a great explosion of light and sound and _force_ Naruto found his world rocked. The chamber door exploded inwards just as a miniature tornado of wind and light formed a protective wall around him. When the dust finally settled his eyes-struggling to remain open despite his exhaustion- were drawn to a mesmerizing sight.

An angel-glowing bright enough to chase away even the deepest shadows-stood before him. As he watched the woman let out a long breath and the aura around her began to subside. When the light had faded to but a dim glow she opened eyes the color of pale gold and addressed him.

"I am Servant Saber, upon your summoning I have come forth. I ask of you…are you my Master?"

"W-what?" he stuttered.

Before the woman could clarify another roar rung out. The two whipped their heads towards the noise and were met with a horrifying sight. A giant of amorphous brown flesh-looking as much like a tree as an animal-towered above them. As they looked on it reached a clawed limb through the opening it had created and pulled itself through, muscle and skin bending at odd angles as if it were boneless. It stood then, fifteen feet at least on its hind legs. An eyeless ogre possessing a mouth of awkwardly jutting fangs.

A bloodthirsty grin stretched across the girl's face. "Ah! It appears we have no time to speak just yet, my lord." She spoke. "Have no fear though, for your humble servant shall slay this foul beast!"

"Wait no! We have to run!" Naruto shouted in panic. He had intended to summon someone who could help him escape! He had no idea if this person could even defeat that thing!

Instead of heeding his words, however, his new comrade ( _'Servant?'_ ) simply drew her sword, stepped in front of him, and raised the weapon to eye level. "Iyeh, Master-ue. To run from battle is simply not in this one's nature, even against a fell beast such as this. Besides, the only way out is through this mongrel!"

As if sensing it had been insulted the monster gave another roar and charged the two at a run.

" **G** A **O** O **O** O **O**!"

The swordswoman merely turned her body to the side with her blade still raised and settled into a definite stance.

The air stilled. Sound bled away. All Naruto could see was her face (set in grim determination despite her euphoric grin) in the reflection of her blade. Pale blond hair flowing gently in sudden breeze.

The beast drew closer.

"Hiken: Mumyou Sandan-Zuki!"

She _moved_. Crossing the distance between her and the beast in a single step, jounin speeds at least, and with a movement that caused Naruto's brain physical pain to follow seemed to unleash three punishing thrusts. _Simultaneously_.

She was back in front of him with another step even as the impossible attack blew a hole through the creature's head and a second, separate, attack severed its knees. It dropped dead mid-run and slid to a stop just inches from her boot-clad feet.

"Hurk!"

Naruto could only choke in shock. This woman-this sprit-was far more powerful than he had imagined. Before he could get a word out, however, she was at his side lifting him onto her back.

"Wha-!"

"Let us depart, Master-ue!" She exclaimed joyfully. With a bloodthirsty grin in place and blade raised she turned towards the literal horde of smaller beasts that had gathered at their sibling's call. "This Servant Saber will defend you till her dying breath!"

"Hold on just a damn second!" he screamed in aggravation and fear.

She leapt. Towards battle and glory. Towards a future fate had not determined.

* * *

 **This one is for all you Fate fans! What started out as a little one shot has become my first crossover and my first (not porn) story. Please respond with constructive criticism and positive reviews. No flames you motherfathers!**

 **Class:** Saber

 **Master:** Uzumaki Naruto

 **True Name:** Okita Souji

 **Gender:** Female

 **Height/Weight:** 158cm/45kg

 **Alignment:** True Neutral

 **Strength:** C

 **Endurance:** E

 **Agility:** A+

 **Magic:** E

 **Luck:** D

 **Noble Phantasm:** C

 **Class Skills:**

 **-Magic Resistance:** E

- **Riding:** E

 **Personal Skills:**

- **Eye of the Mind (False):** A

- **Weak Constitution:** A

- **Reduced Earth:** B

 **Notes:** A noble and traditional Samurai. Because she could not meet her Shinsengumi comrades on the last battlefield due to her illness she wishes to commit herself to 'fighting till the bitter end'. She has low **Magic** **Resistance** because she lived in the Bakumatsu era and her **Riding** is low because she only has experience with horses. Her **Weak Constitution** is due to tuberculosis and causes her to risk a sudden status drop at any moment. The risk is usually minimal but becomes immense in combat. Perhaps a truly Lucky master could offset the this?

 **Hiken: Mumyou Sandan-Zuki** **:** (Concealed Sword: Avidya, Three-Stage Thrust) \- An Anti-Unit Demonic sword skill of the extraordinary genius swordsman Okita Souji. Consisting of a **First Thrust** , **Second Thrust** , and **Third Thrust** , it is a concealed sword that is produced by transcendent technique and speed from the stance of **Hira-Seigan**. Instead of existing at 'almost the same time' the three thrusts exist 'all at the same time' and 'same position'. Even if the First Thrust is blocked the Second and Third would be at the same position and break through. The contradiction this causes creates a localized breakdown in causality at the point of the sword, making it virtually impossible to protect against this technique. Because of the resulting collapse of causal relationships it is a technique that surpasses the simple destruction of material things, similar to **Tsubame-Gaeshi**. For those of you who don't speak 'Nasu-Nerd', her pure skill allows her sword strikes to distort time and space.


End file.
